Receipt printer

A cheap thermal receipt printer is a good desk toy: a to-do list you can tear off and take with you, a shopping list, a note on the fridge, a job ticket stuck to a repair. This page lays the receipt out at the printer’s own resolution and sends it straight from the browser. It’s the long-paper companion to the label maker.

How to use it

Choose a template and fill it in. The preview is the strip of paper, one square per dot, as long as the receipt needs to be.
- To-do list — a title, the date, and a box to tick for each line (start a line with `x ` to print it ticked).
- Shopping list — boxes to tick, grouped under # Aisle headings.
- Note or message — big type, to and from, with the date and time.
- Job card — a shop ticket: the job number white on black, customer, phone, item, the work, parts with prices and dot leaders, the total, the due date, a QR code and a Code 128 barcode of the job.
- Daily agenda — the day in big type, times down the left, tasks to tick, lines for notes.
- Recipe card — ingredients, numbered steps, and a QR code back to the source.
- Wi-Fi guest card — the network, the password if you want it printed, and a QR code that joins.
- Print an image — choose, paste (⌘V / Ctrl+V anywhere on the page) or drop a picture. It’s scaled to the paper and dithered: Floyd–Steinberg for photos, Atkinson for a crisper, lighter look, or none for line art, with a threshold slider. Turn sideways prints a wide picture along the paper.
- Blocks — build your own from headings, text, lists, two columns, rules, QR codes, barcodes, images, space and lines to write on; move them up and down. Edit as blocks on any other template copies it here as a starting point.
  
  2026-10-26 and {time} in any text print today’s date and the time.
Choose the printer — 58 mm ESC/POS (384 dots), 80 mm (576 dots, or 512 on some), or a cat printer.
Connect: Serial port for a USB-serial printer or a Bluetooth printer paired with the computer (it appears as a serial port), USB for a USB printer, Bluetooth for a Bluetooth LE printer.
Print. Set Copies, the Cut and whether to cut after each copy, and Darkness.

How it prints

ESC/POS printers get the receipt as a raster image (GS v 0) in bands of up to 255 rows, then a feed and a cut (GS V). Darkness sends Epson’s print density command; Advanced can also send the heating time (ESC 7) many cheap printers use instead.
Text mode sends plain ESC/POS text in the printer’s own font, with a codepage (PC437, PC850, PC858 or Windows-1252) — fast for text-only receipts. Headings print double size, QR codes and barcodes are made by the printer, and images still go as dots.
Cat printers (GB01, GB02, GB03, MX05, MX06, MX10 and their clones) speak their own Bluetooth protocol — every command framed 51 78 … crc ff with a CRC-8, the rows sent one at a time between "lattice" start and end commands, and darkness set as the head’s energy. I worked it out from NaitLee’s Cat-Printer and the other open-source drivers people have written for them. The page picks the cat protocol by itself when it sees the printer’s AE30 service.
Bluetooth LE printers are written in chunks with a short pause between, because they have small buffers. The page looks for the services cheap printers use (18F0, FF00, E781…, FFE0, the Microchip UART service, AE30); add another UUID under Advanced. If a print comes out garbled, try smaller chunks or a longer pause.

⬇ PNG saves the receipt as an image. 🖨 Other printer… prints it through the browser’s dialog at the paper’s width, for a receipt printer with a system driver.

Browser support

Talking to the printer needs Chrome or Edge on a computer, or Chrome on Android: Web Serial, WebUSB and Web Bluetooth. Safari, Firefox and every browser on iPhone and iPad can still design receipts, download PNGs and use Other printer….

A USB printer that the operating system has already claimed with its own driver can’t be opened over WebUSB. On Windows, swapping its driver for WinUSB with Zadig fixes that; otherwise use the serial port (many USB printers are USB-serial), or Other printer….
A Bluetooth "classic" printer paired with the computer shows up as a serial port; a Bluetooth LE printer (including every cat printer) is reached with Bluetooth.

Privacy

Everything is drawn in this page and sent straight to the printer; nothing you type is uploaded. The page loads qrcode-generator from the jsDelivr CDN when a receipt has a QR code. Images you add stay in this browser. Share link carries the template and what’s in its fields, but never a Wi-Fi password or an image.